During June 2025, ENSO-neutral continued, with near-average sea surface temperatures (SSTs) prevailing across most of the equatorial Pacific Ocean [Fig. 1]. The latest weekly Niño SST index values ranged from 0.0°C to +0.4°C [Fig. 2]. Subsurface temperature anomalies were weakly positive and nearly unchanged from last month [Fig. 3], with mostly above-average temperatures established along the thermocline [Fig. 4]. Over the east-central and eastern equatorial Pacific Ocean, low-level wind anomalies were easterly and upper-level wind anomalies were westerly. Convection remained enhanced over Indonesia [Fig. 5]. Collectively, the coupled ocean-atmosphere system in the tropical Pacific reflected ENSO-neutral.

The IRI predictions indicate ENSO-neutral is most likely through the Northern Hemisphere winter 2025-26 [Fig. 6]. In contrast, the North American Multi-Model Ensemble favors the onset of La Niña conditions during the Northern Hemisphere fall, though lasting a shorter duration than NOAA's requirement of five consecutive overlapping 3-month seasons. While the subsurface equatorial Pacific remains above average, easterly trade winds are predicted to strengthen in the coming month, which could portend cooler conditions. In summary, ENSO-neutral is most likely through the late Northern Hemisphere summer 2025 (56% chance in August-October). Thereafter, chances of La Niña conditions increase into the fall and winter 2025-26, but remain nearly equal to ENSO-neutral [Fig. 7].